are random, meaning they are unrelated to how useful or harmful they might be to the organism in which they occur.

For natural selection to be operating in a population, one of the things that must be present is a particular trait that must be capable of being passed on from parents to offspring. Another word for this is:

inheritable.

The consistent accumulation of mutations that creates differences in the DNA sequences of two diverging groups of organisms is referred to as:

a "molecular clock."

→ Great job. The molecular clock "ticks" over time, and the longer two species have been evolving on their own, the greater the number of changes in amino acid sequences or "ticks of the clock."

All northern elephant seals come from a very small genetic pool. This is because in the 1890s a large number of them were very quickly killed until their population size was reduced to only about 20 individuals. Though their population has since increased to over 30,000 individuals, all their genes have come from those 20 individuals. Which of the following population genetic concepts does this example represent?

the bottleneck effect

Exceptionally large babies increase a mother's mortality risk when giving birth, and exceptionally small babies tend to die at birth or shortly afterward. For these reasons, birth weight in human babies is generally:

subject to stabilizing selection.

"Survival of the fittest" is a misleading phrase. Individuals with the greatest __________ ________ are the most fit in any population.

reproductive output

Estimates of evolutionary relatedness based on a "molecular clock" are supported by:

The first two choices support the molecular clock estimates of evolutionary relatedness.

Which of the following best describes worldwide views before and after Darwin?

BEFORE: A creator put all organisms on earth at the same time. AFTER: Over time, species evolved, but it all started with one organism.

During gene flow, where do the genes flow to?

The genes flow into and out of the population due to migration of individuals from one population to another.

____________ selection favors organisms that have character values at both extremes of the phenotypic distribution.

disruptive

The average time to death from starvation in a fruit fly is about 20 hours. Selecting for increased starvation resistance in fruit flies:

can produce populations in which the average time to death from starvation is 160 hours

Maze-running behavior in mice:

is a heritable trait.

When a group of individuals colonizes a new habitat, this is likely to be an evolutionary event because:

small founding populations are rarely genetically representative of the initial population.

In the 1790s, Georges Cuvier found the fossil remains of mastodons. This conflicted with the prevailing worldview in Europe because:

it meant that extinction must occur, since nothing resembling mastodons existed on earth at that time.

To establish that evolution by natural selection is operating in a population, one must demonstrate variability for a trait, heritability of that trait, differential reproductive success based on that trait, and:

nothing else.

The chief concern among conservation biologists trying to protect small populations is:

to preserve genetic diversity.

When first used in medicine in the 1940s, penicillin was uniformly effective in killing the bacterium Staphylococcus aureus. Today, ____________________ has led to an increase in antibiotic-resistant alleles, and humans are increasingly at risk from untreatable Staphylococcus aureus infections.

a. molecular genetics

b. natural selection in Staphylococcus aureus populations

c. natural selection in human populations

d. uncleanliness in hospitals

e. the substitution of methicillin for penicillin

b. natural selection in Staphylococcus aureus populations

Which of the following illustrates disruptive selection?

a. Female long-tailed widowbirds prefer males with the longest tails.

b. Female starlings that lay four or five eggs per clutch have more surviving young than those with larger or smaller clutches.

c. The most common color form of an insect experiences the heaviest predation.

d. A cattle breeder selects the largest male calf to be the sire for his next herd.

e. Coho salmon eggs tend to be fertilized by the smallest or largest males.

e. Coho salmon eggs tend to be fertilized by the smallest or largest males.

Which of the following statements is NOT consistent with evolution by natural selection?

a. Natural selection can lead to speciation.

b. Certain individuals in a population have a higher rate of reproductive success than other individuals due to a variety of environmental and developmental factors.

c. Individuals change during their lifespans to fit their environment better, and these changes can be inherited by their offspring.

d. Individuals that reproduce most successfully are more likely to have offspring that also reproduce successfully if the environment remains stable.

e. Individuals in a population exhibit variation, some of which can be inherited by their offspring.

c. Individuals change during their lifespans to fit their environment better, and these changes can be inherited by their offspring.

The amount of time that has passed since two species last shared a common ancestor:

a. is revealed by the degree of similarity in sections of their DNA.

b. cannot be determined, due to gaps in the fossil record.

c. cannot be determined, due to the fact that most species pass through the same embryological stages.

d. can be determined for prokaryotic species but not eukaryotes.

e. can be determined by the relative amounts of uranium-238 found in the bones of individuals from each species.

a. is revealed by the degree of similarity in sections of their DNA.

You are studying the allele frequencies of the M and N blood types within a single population. Which of the following choices best describes how you calculate this frequency?

a. Count the number of M and N alleles and divide by the total number of individuals in the population.

b. Count the number of M and N alleles, divide by the total number of alleles and multiply by the total number of individuals in the population

.c. Count the number of M and N alleles and divide by the total number of alleles.

d. Count the number of M and N alleles and multiply by the total number of alleles.

e. None of the above is correct.

c. Count the number of M and N alleles and divide by the total number of alleles.